Some people get pregnant right away, however they aren't always able to sustain the pregnancies(some lucky ones do, though) because the natural progesterone levels had not returned to normal yet, and progesterone is the hormone that builds the lining of the uterus, keeping the embryo protected. I am about 5 months post, and its taken this long for my periods to regulate. I have them every 28 days, but at first they only lasted 1 day (that shows low progesterone) and each period they would get 1 day longer, so now they're at about 4/5 days, wich is normal for me. I feel that if I wanted to get pregnant at this point, I would be able to sustain the pregnancy. I think it's best to wait a few months to make sure your body is 100% ready to not only get pregnant but stay pregnant, rather than try right away and risk a miscarriage. Try a search on this site with the words "pregnant after mirena" and you can read through some posts from others who were ttc after mirena, it may help to see what their experiences were like. Good luck.